Good news for those who don't give up on iris with rot. Last year I got Noble Dragon but quickly lost the mother to rot. I saved three increases. Two of the increases later succumbed to rot. The third one's rhizome was lightly covered by dirt to help it stand upright. Well, that one survived and I planted it yesterday! Over a year later, but I saved a dragon.
Maybe it is Blyth's dragons in general. I thought I lost Puff The Magic this year, but it has two really nice increases now. They are tough!